This application claims priority to and the benefit of Korean Patent Application No. 10-2005-0046850, filed on Jun. 1, 2005, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a plasma display device, and more particularly, to a plasma display device including a plastic chassis.
2. Description of Related Art
Recently, improvements for flat panel display devices have been actively researched. An example of such a flat panel display device is a plasma display device which uses a plasma display panel (PDP). A conventional PDP includes electrodes on two facing substrates, wherein the two substrates overlap at a predetermined interval. A discharge gas is injected between the two substrates, and the two substrates are sealed.
Since a plasma display device can be manufactured to be thinner than a cathode ray tube (CRT), a plasma display device can have a large screen with a small volume and light weight. Also, unlike other flat display devices such as liquid crystal displays (LCD), a plasma display device does not require an active element such as a transistor and has characteristics such as wide viewing angle and high brightness.
A plasma display device is manufactured by forming a PDP and mounting elements required for embodying the screen, such as a driving circuit connected to electrodes on the panel. The PDP is formed by forming conductive patterns and barrier ribs on two glass substrates and overlapping the two glass substrates with each other. The substrates are spaced from each other by the barrier ribs, and the edges of the glass substrates are sealed. Accordingly, it is difficult to directly mount a circuit element on the rear surface of a PDP. Thus, a chassis or a frame is used with the PDP such that a circuit substrate is mountable on the rear surface of the PDP and the fragile PDP is protected and supported.
The chassis is formed by attaching a reinforcement member having various shapes to a chassis base. For example, a reinforcement member having a stepped shape may be mounted on the edge of the chassis base to ensure a uniform strength of the chassis base. Alternatively, a separate reinforcement member may be mounted on a portion of the chassis base using a rivet, a screw, and a welder.
In general, the chassis base is made of iron or aluminum in order to ensure a strength requirement and to allow the chassis base to function as a heat sink and a ground base in the PDP.
In accordance with a recent increase in sizes of plasma display devices, the weight of a metal chassis base used in the chassis has increased, increasing the manufacturing cost of the metal chassis. Accordingly, the chassis must be thin and lightweight to produce a plasma display device having lower power consumption and high quality. However, there is a limit to thickness reduction of the metal chassis base which functions as the frame for mounting the panel and a protective circuit board.
In order to reduce the manufacturing cost of a plasma display device, development of a chassis material having low cost is required. Accordingly, a chassis made of plastic has been researched.
A plastic chassis of the plasma display device may be manufactured by replacing the metal chassis base with a plastic plate and forming a boss for mounting a circuit board on the plastic plate. In this structure, since the same boss as that used in the conventional metal chassis base is mounted on the chassis base and the circuit board is supported by the boss, the plastic chassis is manufactured by only replacing the existing metal plate with the plastic plate.
FIGS. 1 and 2 are a side view and a perspective view, respectively, schematically illustrating a conventional chassis base on which a support frame is mounted.
Conventionally, an ear type chassis base for supporting the corners of the panel is used. However, recently, a structure of forming a wall mount boss 21 on a chassis base 19 and fastening a support frame 25 to the wall mount boss 21 with a screw has been widely adopted, as shown in FIGS. 1 and 2. In this structure, the wall mount boss 21 is formed on the chassis base 19 and a reinforcement member (bracket) 23 into which the wall mount boss is inserted is fastened to the chassis base 19 using a tox method. The tox method is a method of overlapping two thin plates and applying pressure at one side of the plates such that a protrusion and a groove are formed in the plates when viewed at the contact surface. The reinforcement member 23 surrounds a portion of the sidewall of the boss 21 and has flanges at its ends which contact the chassis base 19 to facilitate coupling with the chassis base 19.
One end of the wall mount boss 21 is coupled to the chassis base 19 and another end is fastened to the support frame 25 by a screw 251. The support frame 25 may have various shapes, and functions as an intermediate cover in a plasma display module having a basic circuit. A screen controlling circuit or an operation circuit may be mounted at the rear side of the support frame 25 and a rear case of the plasma display device is provided at the rear side of the circuit. A guide stand hole 27 is formed in the lower side of the support frame 25, into which an upper end of a stand 30 for holding the plasma display device upright is inserted.
In order to manufacture the chassis and the support frame having the aforementioned structure, the chassis base 19, the wall mount boss 21, the reinforcement member (bracket) 23, and the support frame 25 are separately formed, the boss 21 being fastened to the chassis base 19 by a pressing method, the reinforcement member (bracket) 23 being fixed to the chassis base 19 and the boss 21, and the support frame 25 is fastened to the boss 21 with the screw 251.
In this structure, since the components are separately formed and then coupled with one another, the cost required for assembling the components in this manner is increased.